1. Field of the Invention
This application relates to systems including solar heat collectors, and, more particularly to such systems including conduits extending through airspaces within the solar heat collectors with air being heated as it is pumped through the conduits, and yet more particularly such systems in which air from the conduits is used to heat water within a pool, and additionally to such systems in which over-temperature protection is provided.
2. Summary of the Background Art
Conventional solar heating systems for heating pools or hot tubs circulate water from the pool through a solar heat collector. Systems of this kind are known to have disadvantages arising from the fact that pool water is circulated through the entire system, making it difficult to select materials for the components of the system. For example, if copper is used, the pool water is turned green. Furthermore, the solar heat collector of such a system is typically a structure placed on the roof of a house, with the structure having approximately the area of the pool being heated, and with the structure being comprised of a black plastic material that is susceptible to degradation from ultraviolet light and additionally to hurricane damage. Thus, what is needed is a solar heating system in which water from a pool is not circulated through the solar heat collector, preferably with the solar heat collector being located within a separate structure, not necessarily on the roof of a building.
Since heat is added to a solar heat collector at a rate generally dependent on weather conditions and removed from the heat collector at another rate, which is generally dependent on the rate at which the heat is used for various purposes, the solar heat collector itself is subject to overheating. It is therefore desirable to provide over-temperature protection for the airspace within a solar heat collector. A particular benefit of such protection arises from the fact that a solar heat collector having effective over-temperature protection can include materials that would be damaged without over-temperature protection.
The patent literature describes solar heat collectors including an air chamber between a glazed outer surface and a heat absorber through which a working fluid flows to provide heat to another area. The air chamber has openings at each end for receiving air from the atmosphere and for venting air into the atmosphere. To heat the heat absorber, an opening at least at the upper end of the air chamber is closed. When the heat absorber reaches a predetermined maximum temperature, the opening at the upper end or the openings at both ends are opened, so that outside air flows through the air chamber. The patent literature additionally describes an air flow type of solar collector including an air chamber through which air from a structure is circulated. The air chamber also includes openings to outside air at a lower end and at an upper end, both of which can be individually sealed by inflating a flexible tube, allowing different modes of operation under summer and winter conditions. The patent literature further describes water heating solar systems in which water from another source, such as tap water, is added to the water being heated when it is determined to be too hot.